High-Speed Portable Dewpoint Meter TECHNICAL ... · VCO to barbed hose Used above -65°C (-85°F) Make sure sample flow rate is sufficient Use PTFE hoses only VCO to VCO All ranges

TECHNICAL SPECIFICATIONS

DEWPOINT SENSOR ELEMENTType: � � � � � � � � � � � � � � � � � � � � � � Hyper-Thin-Film high capacitance Al2O3Dewpoint range � � � � � � � � � � � � � -100°C to +20°C (-148°F to +68°F)Accuracy: � � � � � � � � � � � � � � � � � � � ± 2°C (±3�6°F ) for -100°C to 0°C Dewpoint ± 3°C (±5�5°F ) for 0°C to +20°C DewpointRepeatability: � � � � � � � � � � � � � � � ±0�5°C (±0�9°F)Response time*: � � � � � � � � � � � � � For a step change from -40°C to -60°C: 63% in 90 seconds; 90% in 450 seconds

TEMPERATURE RANGESensor: � � � � � � � � � � � � � � � � � � � � � � -30°C to +50°C (-22°F to 120°F)Electronics: � � � � � � � � � � � � � � � � � � -10°C to +50°C (14°F to 120°F)Storage temperature: � � � � � � � � -20°C to +60°C (-4°F to +140°F)Sample flow range: � � � � � � � � � � Static to 100 m/s(linear velocity @1atm)

CALIBRATION METHOD

• Multi-point calibration, optionally NIST Traceable• Field calibration based on NIST traceable reference standards (�5ppm to 140 ppm standards)

TEMPERATURE AND PRESSURE MEASUREMENTSThe sample temperature is measured with a precision integrated circuit temperature sensor� Units may be optionally fitted with a pressure sensor�

MECHANICALEnclosure � � � � � � � � � � � � � � � � � � � Anodized Aluminum, Dimensions: 6�4 cm x 10�8 cm x 19�1 cm� Regulator and Filter mounting facilities�Sampling chamber � � � � � � � � � � Electropolished 316 stainless steelMoving parts seals: � � � � � � � � � � Spring energized PTFE seals Pressure operating range:� � � � Standard: 2 bar (29 psig)

Absolute max�: 6�8 bar (100 psig)Gas sample connections: � � � � 1/4” VCO input and output portsElectrical connections: � � � � � � � Optional 2mm DC power jack, 9 pin “D” for analog & RS-232�Power requirements: � � � � � � � � 9v battery and optional 15-25V AC or DC wall transformer�

* These response times are not directly comparable to competitors data, because of differences in measurement methodology and data presentation� Please inquire for detailed comparisons between Xentaur and other major sensor manufacturers�

FEATURESSensor storage: � � � � � � � � � � � � � � When not in use the sensor is retracted in a molecular sieve container and kept at an

approximate dewpoint of -80°C� The sample gas pressure activates a piston which automatically moves the sensor into the sampling chamber, thus even low dewpoints can be measured extremely quickly�

Area classification � � � � � � � � � � � Approved for use in hazardous (classified) areas Class I, Div� 1, Groups A, B, C & D� Available as an option�

Input resolution:� � � � � � � � � � � � � 0�1°C dew point�Indicators:� � � � � � � � � � � � � � � � � � � LCD with backlight, 3�5 digits and custom legends for units and mode, audio alert�Engineering units: � � � � � � � � � � � °C,°F, PPM, lbs H2O/mm scf, g H20/m3

Controls: � � � � � � � � � � � � � � � � � � � � 5 push buttons, all settings stored in EEprom� Manual Sensor Actuator�Outputs: � � � � � � � � � � � � � � � � � � � � Optional 4/20mA or 0/24mA and RS-232�Isolation: � � � � � � � � � � � � � � � � � � � � Sensor and case are isolated from the power supply , analog output and RS-232�Battery saver:� � � � � � � � � � � � � � � � Auto power off after 6 minutes�Pressure correct:� � � � � � � � � � � � � Programmable pressure correction button�

For more detailed technical comparisons with other technologies visit:

rev 3�505

COSA Xentaur CORPORATION

84G Horseblock RD Yaphank, NY 11980 (631) 345-3434 Fax�: (631) 924-7337

email: sales@cosaxenatur�comwww�cosaxentaur�com

High-Speed Portable Dewpoint Meter

MODEL XPDM

QUICK AND PRECISE

SPOT CHECKS OF MOISTURE

-100°C to +20°C (-148°F to +68°F)

www�cosaxentaur�com

EEx ia IIC T4Nemko Nr�Ex 99E269

INTRINSICALLY SAFE FORCLASS I, DIV1, GROUPS A, B, C, & D

T4 at 40APPROVED

APPLICATIONS• Industry Leader in Electrical

Insulating Gases, SF6 Measurements

• Key Supplier to Largest Natural Gas Pipeline System

• Exclusive Supplier to Leading Cryogenic and Specialty Gases Producers

• Petrochemical Industry’s Choice for Portable Measurement

• Recommended by the Leading Military Research Institutes for Welding and Joining Gases Measurement

• Aerospace

• Heat treating

• Medical & Breathing Air

• LNG, LPG

• Many Others Manufactured with pridein the USA

Type of Adapter Range Remarks

VCO to barbed hose Used above -65°C (-85°F)

Make sure sample flow rate is sufficient�

Use PTFE hoses only

VCO to VCO All ranges

Where flexible connection is required,

use flexible stainless steel hoses

VCO to Swagelok All rangesWhere rigid

connections are acceptable

SENSOR IN DRY STORAGE POSITION

SENSOR INMEASURING POSITION

1 Sample Gas IN 2 Sample Gas OUT 3 Piston 4 Sample Cell 5 Sensor 6 Spring loaded Teflon Seal

1010

5

5

3

3

77

7

1

8

1

1111

4

46

22

7 Sensor Actuator 8 Desiccant Chamber 9 Filter Mesh10 Electronic Board11 Instrument Case

6

6

6

99

OVERVIEWThe portable Dewpoint Meter Model XPDM is a battery oper-ated, hand-held instrument, designed for applications where quick and accurate dewpoint measurements have to be made� With the XPDM, accurate spot-checks of moisture in gases can be made faster and easier than ever, over the range of -100°C to +20°C (-148°F to +68°F) dewpoint�

APPLICATIONSImportant uses of the XPDM include: petrochemical, feedstock gases, instrument air, transformer and switch gear insulating gases, gas cylinders and air separation plants, welding gases, shipboard LNG and aviation oxygen, transfer standard, cus-tody transfer and others�

OPERATING PRINCIPLEAluminum oxide sensors adsorb much faster than they desorb water molecules� It is therefore an advantage, if at the beginning of the measurement the sensor is dryer than the sample to be measured� The XPDM keeps the sensor in dry storage until the measurement is taken� The sensor slides directly from the dry storage into the sample cell, without ever coming in contact with ambient air� After the measurement is completed, the sensor slides back into the dry storage, where it is dried down for the next sample�

DRY STORAGE SYSTEMThe diagram above shows the mechanical design of the XPDM dry storage sample cell system� The picture on the left shows the sensor immersed into the desiccant for dry storage� The sensor is sepa-rated from the desiccant by a very fine stainless steel mesh with a thickness of approximately 5 mm� Close proximity of the sensor to the desiccant is crucial for fast dry down� With the sensor in the dry storage position, the sample flows through the head space between the bottom of the sample cell and the sensor piston� In order to take a measurement, the gas outlet is blocked temporarily� The pressure of the sample flow pushes the piston and pulls the sensor into the sample cell, where it wets up quickly to the moisture content in the sample flow� An accurate reading can be taken within 1 to 2 min-utes� Afterwards, the sensor is pushed back into the dry storage po-sition by means of the sensor actuator which protrudes through the front of the instrument�

SAMPLE CELL DESIGNAll surfaces in contact with the sample are made from 316 stainless steel and are electropolished to assure rapid equilib-rium with the sample� Sensor and piston slide through spring-loaded PTFE seals protecting the sample cell as well as the desiccant cartridge from intrusion of wet air or gas�

The sample cell can measure gas flows of up to 20 liters per minute� The flow rate has no effect on the measurement� The pressure in the sample cell is near atmospheric and should not exceed 2 bar (29 psi)�

The instrument computer gives a read out at sensor pressure as well as at any line pressure the user enters for the particular sample� No correction is needed for different gases�

SAMPLE CONNECTIONSSample connections can be made by means of a variety of dif-ferent fittings, depending on the application� The primary port fittings are 1/4” VCO� The following table shows the recom-mended fittings for different dewpoint ranges and instrument uses:

FIELD EXCHANGEABLE DESICCANT CARTRIDGEThe desiccant cartridge and its connection to the sample cell have been designed for maximum gas tightness� The sensor move-ment between desiccant chamber and sample cell occurs with a minimum amount of gas transfer� Thus, the desiccant life is prolonged� The desiccant can be replaced in the field in a matter of minutes, by simply exchanging the cartridge�

SPAN CHECK WITHOUT REFERENCE

STANDARDSCOSAXentaur HTF™ high capacitance sensors have a very low re-sidual capacitance when dry, and saturate at a predesigned level of humidity above +20°C (+68°F)� This allows a span check of the sensor by cupping the sensor in the palm of one’s hand for one minute, and adjusting the instrument to its upper range limit� The advantages of this span check system are obvious: Xentaur sensors can be field calibrated anywhere, anytime without using expensive and cumbersome calibration standards� Sensors do not have to be returned to the factory for recalibration, which also eliminates the need for a second stand-by sensor�

The HTF™ aluminum oxide sensor installed in the model XPDM is the product of years of intensive research at the laboratories of Xentaur Corporation� It offers significant performance advantages over all other aluminum oxide moisture sensors�

The operating principle is similar to that of other aluminum oxide sensors: a hygroscopic layer of aluminum oxide adsorbs or releases

water molecules within its pores, depending on the water vapor pressure in its environment� Thus, the electrical capacitance of the aluminum oxide layer changes with the surrounding water vapor pressure� The electrical capacitance is measured between the aluminum core of the sensor and a porous conductive gold layer on the outside�

The advantage of the Xentaur sensor is a proprietary manufacturing method in which the aluminum oxide layer is made to be hyper-thin as well as extremely hygroscopic� This results in a very sensitive sensor with fast response�

HIGH CAPACITANCE RESPONSEDue to the HTF™ Hyper-Thin-Film and a special pore geometry, Xentaur sensors have a capacitance change over their full range, several orders of magnitude larger than that of conventional aluminum oxide sensors� Additionally, this change is quasi-linear and its sensitivity to temperature is negligible�

The advantages of a linear high capacitance response are: better sensitivity, better repeatability and faster response times� Also, the measurement system is less prone to noise and drift, and signal conditioning is kept to a minimum�

COSAXENTAUR HYPER-THIN-FILM (HTF™) Al2O3 MOISTURE SENSOR TECHNOLOGY

Faceplate Actual Size

x10-3

PPM C FLBSDEWPOINT PSI G/M3

SET %HILOTEMP

XPDMXENTAUR PORTABLE DEWPOINT METER

Aluminum

Aluminum Oxide Film with Pores

Gold layer

Operating Principle of Al2O3

USER INTERFACEThe instrument is operated through a simple user interface consisting of a digital LCD display, and four push buttons�

The user can select from the following engineering units:• dewpoint in °C or °F• ppmv• lbs H2O/ million scf� (Natural Gas)• grams of H2O/m3 (Natural Gas)

Results are displayed at sensor pressure (atmo-spheric) or by pushing the Pressure Correct key at a user selectable alternative pressure, such as the line pressure�

POWER SUPPLY AND SIGNAL OUTPUTThe instrument is powered by a 9V battery which lasts for 100 hours of continuous operation� An automatic shut-off feature makes sure that the battery is not kept in use unnec-essarily�

Optionally, the instrument can be equipped with an external power supply jack and signal output board� The instrument can then operate from 15 - 20 V AC or DC, or from a car battery adapter� All signal outputs are isolated from the sensor� The analog out-put can be current or voltage� The RS-232 output can be easily connected to a PC or a modem�

-90

-70

-50

-30

-10 10 30

Dewpoint (˚C)

200

150

100

50

0

nF

200

150

100

50

0

XDO�D�BR�0001

Type of Adapter Range Remarks

VCO to barbed hose Used above -65°C (-85°F)

Make sure sample flow rate is sufficient�

Use PTFE hoses only

VCO to VCO All ranges

Where flexible connection is required,

use flexible stainless steel hoses

VCO to Swagelok All rangesWhere rigid

connections are acceptable

SENSOR IN DRY STORAGE POSITION

SENSOR INMEASURING POSITION

1 Sample Gas IN 2 Sample Gas OUT 3 Piston 4 Sample Cell 5 Sensor 6 Spring loaded Teflon Seal

1010

5

5

3

3

77

7

1

8

1

1111

4

46

22

7 Sensor Actuator 8 Desiccant Chamber 9 Filter Mesh10 Electronic Board11 Instrument Case

6

6

6

99

OVERVIEWThe portable Dewpoint Meter Model XPDM is a battery oper-ated, hand-held instrument, designed for applications where quick and accurate dewpoint measurements have to be made� With the XPDM, accurate spot-checks of moisture in gases can be made faster and easier than ever, over the range of -100°C to +20°C (-148°F to +68°F) dewpoint�

APPLICATIONSImportant uses of the XPDM include: petrochemical, feedstock gases, instrument air, transformer and switch gear insulating gases, gas cylinders and air separation plants, welding gases, shipboard LNG and aviation oxygen, transfer standard, cus-tody transfer and others�

OPERATING PRINCIPLEAluminum oxide sensors adsorb much faster than they desorb water molecules� It is therefore an advantage, if at the beginning of the measurement the sensor is dryer than the sample to be measured� The XPDM keeps the sensor in dry storage until the measurement is taken� The sensor slides directly from the dry storage into the sample cell, without ever coming in contact with ambient air� After the measurement is completed, the sensor slides back into the dry storage, where it is dried down for the next sample�

DRY STORAGE SYSTEMThe diagram above shows the mechanical design of the XPDM dry storage sample cell system� The picture on the left shows the sensor immersed into the desiccant for dry storage� The sensor is sepa-rated from the desiccant by a very fine stainless steel mesh with a thickness of approximately 5 mm� Close proximity of the sensor to the desiccant is crucial for fast dry down� With the sensor in the dry storage position, the sample flows through the head space between the bottom of the sample cell and the sensor piston� In order to take a measurement, the gas outlet is blocked temporarily� The pressure of the sample flow pushes the piston and pulls the sensor into the sample cell, where it wets up quickly to the moisture content in the sample flow� An accurate reading can be taken within 1 to 2 min-utes� Afterwards, the sensor is pushed back into the dry storage po-sition by means of the sensor actuator which protrudes through the front of the instrument�

SAMPLE CELL DESIGNAll surfaces in contact with the sample are made from 316 stainless steel and are electropolished to assure rapid equilib-rium with the sample� Sensor and piston slide through spring-loaded PTFE seals protecting the sample cell as well as the desiccant cartridge from intrusion of wet air or gas�

The sample cell can measure gas flows of up to 20 liters per minute� The flow rate has no effect on the measurement� The pressure in the sample cell is near atmospheric and should not exceed 2 bar (29 psi)�

The instrument computer gives a read out at sensor pressure as well as at any line pressure the user enters for the particular sample� No correction is needed for different gases�

SAMPLE CONNECTIONSSample connections can be made by means of a variety of dif-ferent fittings, depending on the application� The primary port fittings are 1/4” VCO� The following table shows the recom-mended fittings for different dewpoint ranges and instrument uses:

FIELD EXCHANGEABLE DESICCANT CARTRIDGEThe desiccant cartridge and its connection to the sample cell have been designed for maximum gas tightness� The sensor move-ment between desiccant chamber and sample cell occurs with a minimum amount of gas transfer� Thus, the desiccant life is prolonged� The desiccant can be replaced in the field in a matter of minutes, by simply exchanging the cartridge�

SPAN CHECK WITHOUT REFERENCE

STANDARDSCOSAXentaur HTF™ high capacitance sensors have a very low re-sidual capacitance when dry, and saturate at a predesigned level of humidity above +20°C (+68°F)� This allows a span check of the sensor by cupping the sensor in the palm of one’s hand for one minute, and adjusting the instrument to its upper range limit� The advantages of this span check system are obvious: Xentaur sensors can be field calibrated anywhere, anytime without using expensive and cumbersome calibration standards� Sensors do not have to be returned to the factory for recalibration, which also eliminates the need for a second stand-by sensor�

The HTF™ aluminum oxide sensor installed in the model XPDM is the product of years of intensive research at the laboratories of Xentaur Corporation� It offers significant performance advantages over all other aluminum oxide moisture sensors�

The operating principle is similar to that of other aluminum oxide sensors: a hygroscopic layer of aluminum oxide adsorbs or releases

water molecules within its pores, depending on the water vapor pressure in its environment� Thus, the electrical capacitance of the aluminum oxide layer changes with the surrounding water vapor pressure� The electrical capacitance is measured between the aluminum core of the sensor and a porous conductive gold layer on the outside�

The advantage of the Xentaur sensor is a proprietary manufacturing method in which the aluminum oxide layer is made to be hyper-thin as well as extremely hygroscopic� This results in a very sensitive sensor with fast response�

HIGH CAPACITANCE RESPONSEDue to the HTF™ Hyper-Thin-Film and a special pore geometry, Xentaur sensors have a capacitance change over their full range, several orders of magnitude larger than that of conventional aluminum oxide sensors� Additionally, this change is quasi-linear and its sensitivity to temperature is negligible�

The advantages of a linear high capacitance response are: better sensitivity, better repeatability and faster response times� Also, the measurement system is less prone to noise and drift, and signal conditioning is kept to a minimum�

COSAXENTAUR HYPER-THIN-FILM (HTF™) Al2O3 MOISTURE SENSOR TECHNOLOGY

Faceplate Actual Size

x10-3

PPM C FLBSDEWPOINT PSI G/M3

SET %HILOTEMP

XPDMXENTAUR PORTABLE DEWPOINT METER

Aluminum

Aluminum Oxide Film with Pores

Gold layer

Operating Principle of Al2O3

USER INTERFACEThe instrument is operated through a simple user interface consisting of a digital LCD display, and four push buttons�

The user can select from the following engineering units:• dewpoint in °C or °F• ppmv• lbs H2O/ million scf� (Natural Gas)• grams of H2O/m3 (Natural Gas)

Results are displayed at sensor pressure (atmo-spheric) or by pushing the Pressure Correct key at a user selectable alternative pressure, such as the line pressure�

POWER SUPPLY AND SIGNAL OUTPUTThe instrument is powered by a 9V battery which lasts for 100 hours of continuous operation� An automatic shut-off feature makes sure that the battery is not kept in use unnec-essarily�

Optionally, the instrument can be equipped with an external power supply jack and signal output board� The instrument can then operate from 15 - 20 V AC or DC, or from a car battery adapter� All signal outputs are isolated from the sensor� The analog out-put can be current or voltage� The RS-232 output can be easily connected to a PC or a modem�

-90

-70

-50

-30

-10 10 30

Dewpoint (˚C)

200

150

100

50

0

nF

200

150

100

50

0

XDO�D�BR�0001

TECHNICAL SPECIFICATIONS

DEWPOINT SENSOR ELEMENTType: � � � � � � � � � � � � � � � � � � � � � � Hyper-Thin-Film high capacitance Al2O3Dewpoint range � � � � � � � � � � � � � -100°C to +20°C (-148°F to +68°F)Accuracy: � � � � � � � � � � � � � � � � � � � ± 2°C (±3�6°F ) for -100°C to 0°C Dewpoint ± 3°C (±5�5°F ) for 0°C to +20°C DewpointRepeatability: � � � � � � � � � � � � � � � ±0�5°C (±0�9°F)Response time*: � � � � � � � � � � � � � For a step change from -40°C to -60°C: 63% in 90 seconds; 90% in 450 seconds

TEMPERATURE RANGESensor: � � � � � � � � � � � � � � � � � � � � � � -30°C to +50°C (-22°F to 120°F)Electronics: � � � � � � � � � � � � � � � � � � -10°C to +50°C (14°F to 120°F)Storage temperature: � � � � � � � � -20°C to +60°C (-4°F to +140°F)Sample flow range: � � � � � � � � � � Static to 100 m/s(linear velocity @1atm)

CALIBRATION METHOD

• Multi-point calibration, optionally NIST Traceable• Field calibration based on NIST traceable reference standards (�5ppm to 140 ppm standards)

TEMPERATURE AND PRESSURE MEASUREMENTSThe sample temperature is measured with a precision integrated circuit temperature sensor� Units may be optionally fitted with a pressure sensor�

MECHANICALEnclosure � � � � � � � � � � � � � � � � � � � Anodized Aluminum, Dimensions: 6�4 cm x 10�8 cm x 19�1 cm� Regulator and Filter mounting facilities�Sampling chamber � � � � � � � � � � Electropolished 316 stainless steelMoving parts seals: � � � � � � � � � � Spring energized PTFE seals Pressure operating range:� � � � Standard: 2 bar (29 psig)

Absolute max�: 6�8 bar (100 psig)Gas sample connections: � � � � 1/4” VCO input and output portsElectrical connections: � � � � � � � Optional 2mm DC power jack, 9 pin “D” for analog & RS-232�Power requirements: � � � � � � � � 9v battery and optional 15-25V AC or DC wall transformer�

* These response times are not directly comparable to competitors data, because of differences in measurement methodology and data presentation� Please inquire for detailed comparisons between Xentaur and other major sensor manufacturers�

FEATURESSensor storage: � � � � � � � � � � � � � � When not in use the sensor is retracted in a molecular sieve container and kept at an

approximate dewpoint of -80°C� The sample gas pressure activates a piston which automatically moves the sensor into the sampling chamber, thus even low dewpoints can be measured extremely quickly�

Area classification � � � � � � � � � � � Approved for use in hazardous (classified) areas Class I, Div� 1, Groups A, B, C & D� Available as an option�

Input resolution:� � � � � � � � � � � � � 0�1°C dew point�Indicators:� � � � � � � � � � � � � � � � � � � LCD with backlight, 3�5 digits and custom legends for units and mode, audio alert�Engineering units: � � � � � � � � � � � °C,°F, PPM, lbs H2O/mm scf, g H20/m3

Controls: � � � � � � � � � � � � � � � � � � � � 5 push buttons, all settings stored in EEprom� Manual Sensor Actuator�Outputs: � � � � � � � � � � � � � � � � � � � � Optional 4/20mA or 0/24mA and RS-232�Isolation: � � � � � � � � � � � � � � � � � � � � Sensor and case are isolated from the power supply , analog output and RS-232�Battery saver:� � � � � � � � � � � � � � � � Auto power off after 6 minutes�Pressure correct:� � � � � � � � � � � � � Programmable pressure correction button�

For more detailed technical comparisons with other technologies visit:

rev 3�505

COSA Xentaur CORPORATION

84G Horseblock RD Yaphank, NY 11980 (631) 345-3434 Fax�: (631) 924-7337

email: sales@cosaxenatur�comwww�cosaxentaur�com

High-Speed Portable Dewpoint Meter

MODEL XPDM

QUICK AND PRECISE

SPOT CHECKS OF MOISTURE

-100°C to +20°C (-148°F to +68°F)

www�cosaxentaur�com

EEx ia IIC T4Nemko Nr�Ex 99E269

INTRINSICALLY SAFE FORCLASS I, DIV1, GROUPS A, B, C, & D

T4 at 40APPROVED

APPLICATIONS• Industry Leader in Electrical

Insulating Gases, SF6 Measurements

• Key Supplier to Largest Natural Gas Pipeline System

• Exclusive Supplier to Leading Cryogenic and Specialty Gases Producers

• Petrochemical Industry’s Choice for Portable Measurement

• Recommended by the Leading Military Research Institutes for Welding and Joining Gases Measurement

• Aerospace

• Heat treating

• Medical & Breathing Air

• LNG, LPG

• Many Others Manufactured with pridein the USA